Advanced Graphics Port that extends the PCI bust and overcomes the limitation of PCI for handling large amounts of 3D graphics. The AGP had a bandwidth of 133MHz.

Alpha Blending

A visual effect that mixes two textures on the same object.

Anti-Aliasing

The process of smoothing graphics in order to achieve a higher quality image on-screen.

Bilinear Filtering

Averages the four nearest texels (textured pixels) to generate a higher picture quality. Used by some OEMs to make textures appear smoother and without blockiness.

Bus

Most commonly means the data pathway that connects a processor to memory or other peripheral buses, such as PCI and AGP that connect to the system.

Color Depth

The amount of colors displayable on your monitor such as 16-bit High Color (16.7 million color) or True 24-bit or True 32-bit Color (Unlimited Colors)

Direct3D

A type of API (Application Programming Interface) from Microsoft that sends 3D application instructions to the hardware that will display it. To take advantage of the Direct3D, both the application and the graphics card used must support Direct3D. This API is part of the DirectX standard.

Frame Buffer

The memory on a graphics card that stores rendered frames not being displayed on screen. They are then converted by the RAMDAC and displayed.

Fogging

Used to hide the background of a scene, usually a landscape, behind a layer of fog, requiring the mixing of the textures' color values with a monochrome color, such as white.

Gouraud Shading

Giving the effect of shading to 3D objects by dividing surfaces into small triangles and applying different shades of color.

Memory bandwidth

The data-carrying capacity and typically expressed in Hertz (Hz) but it is also common to use bits instead. In the case of RAM, bandwidth is a function of its rated speed and the size of its data path.

MIP Mapping

To improve the quality of mapped 3D textures, three copies or MIP levels of the same texture are made in different sizes to fit an object. The three forms of MIP Mapping are tile-base, per-pixel, and tri-linear.

Palletized Textures

Assigning a Color Look-Up-Table (CLUT) to each texture in a scene. More memory efficient than using the normal 16-bit color value.

PCI

Peripheral Component Interface was designed by Intel to be self-configuring in order to ease the installation of PCI components that will take and use available interrupts in the system without manual configuration. PCI has a 33-66MHz bandwidth smaller than the AGP at 133MHz bandwidth.

RAMDAC

Random Access Memory Digital to Analogue Converter which is embedded in the controller that sits on a graphics accelerator board. The RAMDAC translates the digital representation of a screen-full of information into an analog signal that the monitor can then display. The faster the RAMDAC (measured in MHz), the higher the screen refresh rates that the card will support at a given resolution.

Refresh Rate

The measurement of times per second a monitor screen is repainted. This is measured in Hertz (Hz). A slow refresh rate will cause the screen to flicker.

Rendering

The process of producing bitmapped images from a view of 3D models in a 3D scene. A camera is placed at a location, pointing in agiven direction. Animation is a series of such renderings, each with the scene slightly changed.

Resolution

The number of horizontal pixels times the number of vertical lines. This gives you the total number of pixels that can be displayed by your monitor. The higher the resolution, the sharper the image.

SDRAM

Synchronous Dynamic Random Access Memory is faster than the standard DRAM and incorporates new features such as running at a bus speed of 100MHz.

SGRAM

Synchronous Graphics Random Access Memory contains the speed-enhancing features of SDRAM and adds graphics capabilities that enhance 3D graphics performance. Like SDRAM, SGRAM can work in sync with system bus speeds up to 100MHz.

Texel

A texture element like its cousin the pixel, a texel is the base unit of a graphic. While pixels are the basic elements in any graphic, texels are their equivalent in a texture map.

Texture Mapping

Applying a two-dimensional textures to 3D objects or scenes to make them appear more realistic.

Trilinear Filtering

Like its less sophisticated cousin, bilinear texture filtering, trilinear filtering is a complex technique used by 3D graphics cards to make movement through rendered landscapes realistic even in fast-moving games.

Z-Buffering

When two objects are intersecting each other, the z-buffer determines which portions of the intersecting objects are visible.

Date of last revision: 17 December 2001. Extracted from the Imaging Magazine, August 1998.